To date, a medical instrument (also referred to as a medical device) in which a manipulation wire rope or the like is used as one of components, has been known. As such a medical instrument, for example, an endoscope treatment instrument disclosed in JPH8-126648 is known. In the endoscope treatment instrument, an operation unit being held by hand and a treatment unit provided at its leading end are connected by a manipulation wire rope having torque transmittability. An operator inserts the treatment unit into a body cavity of a patient and operates the operation unit, whereby an operating force thereof is transmitted to the treatment unit by the manipulation wire rope. The manipulation wire rope allows a pushing force, a pulling force, and a rotational force (torque) to be transmitted from the operation unit to the treatment unit. By the transmitted force, a portion, of a body, to be treated can be subjected to medical treatment.
The manipulation wire rope is required to have not only transmittability of pushing and pulling force, but also an excellent torque transmittability (rotation followability) according to application of the manipulation wire rope. In a case where a torque transmittability or the like of the manipulation wire rope is insufficient, an operation of the operation unit is not reproduced by the treatment unit. Furthermore, particularly in the field of medical devices, the manipulation wire rope is required to have flexibility according to the diameter of the medical device being reduced.
JPH6-63142 discloses a coil-shaped pipe used as a catheter for diagnosis and treatment. The pipe is formed by a metal wire material being wound into a coil. In the pipe, the coils adjacent to each other are in pressure contact with each other by an initial restoring force due to forming of the coil shape. This catheter is also required to have flexibility, pushability included in transmittability of pushing and pulling force, torque transmittability, and the like, as described above.